U.S. Pat. No. 3,984,574, issued to Comollo, discloses an adhesive (non-tack) gum base in which the non-tack properties were achieved by eliminating conventional gum base ingredients found to contribute to chewing gum tackiness, and substituting non-tacky ingredients in their place. Specifically, it was discovered that some elastomers, resins and waxes contribute to chewing gum tackiness.
Comollo eliminated natural and some synthetic elastomers from gum base, and substituted non-tacky synthetic elastomers such as polyisobutylene, polyisoprene, isobutylene-isoprene copolymer and styrene-butadiene copolymer. Comollo also eliminated tack-producing natural resins and modified natural resins, and replaced them with higher amounts of hydrogenated or partially hydrogenated vegetable oils or animal fats. Also, Comollo excluded waxes from the gum base, but included polyvinyl acetate, fatty acids and mono and diglycerides of fatty acids.
Other efforts to develop tack-free gum bases and chewing gums are also known in the art. For example, U.S. Pat. No. 4,415,593, issued to Glass et al., discloses a non-stick chewing gum in which the gum base includes polyisoprene obtained from a naturally occurring guayule rubber. U.S. Pat. No. 4,387,108, issued to Koch et al., discloses a reduced tack gum base containing an elastomer, lecithin or lecithin derivatives, glycerol ester of partially hydrogenated wood rosin, a mineral adjuvant, a non-toxic vinyl polymer, and an oleaginous plasticizer. U.S. Pat. No. 5,087,459, issued to Chuu et al., discloses a non-tack chewing gum whose gum base includes a terpene resin, high melting wax, low melting wax, elastomer, polyvinyl acetate, emulsifier, filler, and gum base solvent. Other non-tack gum bases and gums are also known.
A problem with many non-tack chewing gums is that the gum base ingredients which caused product tackiness also provided cohesive forces which held the gum base and chewing gum together. Thus, when tackiness is eliminated by removing certain ingredients or combinations of ingredients, the resulting chewing gum base would often break apart into distinct loaves or chunks which would not mix and disperse properly during manufacture of the chewing gum. The resulting chewing gum product would often exhibit short texture, meaning that it was easy to break, separate or crumble. In the case of sugarless non-tack gums, some of the non-tack gum bases produced undesirable sensory qualities such as a burning flavor. Therefore, there is a need or desire in the chewing gum industry for a non-tack gum base and chewing gum which exhibit ample cohesive bonding between the ingredients notwithstanding the absence of tackiness to external surfaces such as teeth and dentures, and which have improved sensory qualities.